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US 12,406,777 B2Granted
Optical element for a EUV projection exposure system
AssigneeCarl Zeiss SMT GmbH
InventorsHartmut Enkisch, Sandro Hoffmann, Joern Weber, Sebastian Strobel, Mirko Ribow, Christoph Nottbohm, Matthias Sturm, Michael Krause
Life of this patent
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Abstract
In a method for producing an optical element for an EUV projection exposure apparatus, a shaping layer (221) is applied onto a substrate (20) so as to have a surface roughness of at most 0.5 nm rms directly after the application of the shaping layer onto the substrate.
Claims14
An optical element for an extreme ultraviolet (EUV) projection exposure apparatus, comprising:
- a substrate specifying a curved basic topography,
- at least two shaping layers, applied onto the substrate, each with a layer thickness (Di(s)) according to a specified layer thickness profile (Div(s)),
- a plurality of etch stop layers,
- an EUV radiation-reflecting layer,
- wherein at least one of the shaping layers is structured to form a grating structure with a bottom region, a front side, and a flank,
- wherein a transition from the bottom region to the flank has a radius of curvature of at most 5 μm, and
- wherein the EUV-radiation-reflecting layer is applied at least to the bottom region and to the front side of the grating structure.
4 more elements
A method for producing an optical element for an extreme ultraviolet (EUV) projection exposure apparatus, comprising:
- providing a substrate with a basic topography,
- applying a shaping layer onto the substrate with a layer thickness (Di(s)) according to a specified layer thickness profile (Div(s)),
- applying an etch stop layer, wherein the etch stop layer is applied under the shaping layer,
- wherein the shaping layer has a surface roughness of at most 0.5 nm rms directly after said applying onto the substrate,
- wherein all of the layers are applied in vacuum conditions, wherein the vacuum is maintained between said applying of the shaping and the etch stop layers.
2 more elements
Dependencies are inferred from the claim text.